Whether you call Edward Snowden a traitor or a whistle-blower, he earned one label about which there’s no debate: insider threat.

Guarding against such risks is an expanding niche in the security industry, with at least 20 companies marketing software tools for tracking and analyzing employee behavior. “The bad guys helped us,” says Idan Tendler, the founder and chief executive officer of Fortscale Security in San Francisco. “It started with Snowden, and people said, ‘Wow, if that happened in the NSA, it could happen to us.’ ”

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Companies are also realizing that tracking insiders may improve their odds of catching outside hackers.